The invention relates to a pipe made of concrete having a corrosion-resistant inner lining consisting of a plastic pipe in accordance with the description herein.
The invention relates to a pipe made of concrete having a common-resistant inner lining consisting of a plastic pipe in accorance with the preamble of claim 1.
Pipes made both of concrete and of plastic are known. In the latter case, they are mainly drawn from plastic, whereas the pipes produced from concrete are manufactured in an upright form known per se with a displaceable core. These pipes, which are largely used in drainage systems, are subject to demands within the framework of environmental protection which are increasing all the time and which hardly satisfy today's needs any more. This is above all due to the fact that they corrode faster under wastewater which is more and more aggressive and of high acid content and therefore become leaky or are destroyed. Such corrosion, however, also makes a constant replacement and ultimately a relaying of new pipes necessary more frequently than was required only a few years ago. To avoid these disadvantages, it has already become known to manufacture concrete pipes in conjunction with a plastic pipe. Since these pipes are rigidly connected in a customary manner, like concrete pipes, in each case with their one spigot end inserted into the next following wide pipe end of socket shape, these spigots break easily. These pipes are moreover exposed to strain-induced cracking of the concrete body and/or to a bursting of the concrete pipe ends which have been plugged together as a consequence of their rigid, solid assembly due to a lack of sufficient precautions for temperature-induced expansion possibilities of the plastic parts to the concrete parts and the concrete parts to the concrete parts so that these pipe parts are destroyed for this reason and have to be replaced with new pipes.
A concrete pipe having a corrosion-resistant inner lining consisting of a plastic pipe is already known from DE-U-8 132 729 whose one end is made as a pipe spigot end part and whose other end is made as a pipe socket end part to receive a pipe spigot end part of the following pipe, with the plastic pipe projecting by an overhang at the pipe spigot end, with an all-round peripheral grooving being arranged between the end facing end of the pipe socket end part and an all-round peripheral shoulder springing into the pipe interior at the pipe interior of the plastic pipe to receiver an elastomer sealing ring, with the overhang extending in a straight line and insertable into the pipe socket end part being so long that it covers the peripheral grooving with its sealing ring and with the pipe made of concrete covering the plastic pipe up to the insertable overhang of the pipe spigot end part, with the all-round peripheral shoulder of the inwardly lying plastic pipe being chamfered.
A pipe made of concrete having a corrosion-resistant inner lining made of plastic is known from DE-U-8 806 158 in which a bond-tight union takes place between the concrete jacket and the plastic liner. This can result in stress-induced destruction due to the different thermal expansion coefficient of the materials in practical use.
Finally, a concrete pipe is known from EP 426 147 B 1. With this concrete pipe, the pipe spigot end part consisting of a plastic is already sealed by a seal with respect to the pipe interior of the adjacent pipe likewise consisting of plastic. An all-round peripheral, annular seal made of flexible material is furthermore arranged between the pipe socket end part consisting only of concrete and the concrete pipe spigot end part of the adjacent pipe. These pipes have been able to establish themselves as corrosion-resistant pipes for some years due to their obvious advantages. However, it can be found with these pipes that they do not always withstand the obligatory air pressure test after being laid. This means that leaky points can arise in the region of the pipe transitions through which the pumped-in compressed air can escape.